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Biomedical subjects

A Matrai

Publications and source records attributed to A Matrai.

At least 19 recordsLinked to original sources
PubMed1992

Fibrinogen and viscosity as risk factors for subsequent cardiovascular events in stroke survivors.

OBJECTIVE: To investigate whether abnormalities in blood viscosity predict a poor prognosis for subsequent cardiovascular events in stroke survivors. DESIGN: Nested case-control study among a cohort of survivors of a first stroke, followed for an average of 2 years. Patients with a second stroke, myocardial infarction, or cardiovascular death were matched with patients who did not have such events (control patients). SETTING: Buchberg-Klinik, Bad Tölz, Germany, a specialized center for stroke rehabilitation. PATIENTS: A total of 625 consecutive patients. Twenty-one patients (3.5%) were lost to follow-up. Sixty pairs were matched. MEASUREMENTS: Native and hematocrit-standardized blood viscosity at three shear rates, hematocrit, plasma viscosity, fibrinogen, erythrocyte sedimentation rate, total leukocyte count, and the matching variables. RESULTS: Eighty-five patients had a second stroke, myocardial infarction, or died due to a cardiovascular event. Patients with re-events had higher blood viscosity and fibrinogen levels than the control patients. In the 60 matched pairs, the mean of the paired differences between patients with re-events and control patients was 5.03 mPa.s (95% CI, 1.262 to 8.941; P = 0.01) for native blood viscosity at shear rate 0.7 s-1, for plasma viscosity, 0.044 mPa.s (CI, 0.006 to 0.083; P greater than 0.02), and for fibrinogen, 0.056 g/L (CI, 0.010 to 0.101; P greater than 0.02). Odds ratios were significantly increased only for plasma viscosity (odds ratio, 2.86; CI, 1.06 to 8.43) and fibrinogen (odds ratio, 3.67; CI, 1.31 to 11.69). CONCLUSIONS: Hyperfibrinogenemia is an independent risk factor for cardiovascular events in stroke survivors. Intervention trials with fibrinogen lowering measures may be warranted.

Aged↗
PubMed1992

A viscometric method of measuring plasma fibrinogen concentrations.

A technique based on deducing the viscosity of serum from that of plasma was compared with the commonly used Clauss method. The two methods correlated closely (r = 0.914). The reproducibility of the viscometric method was slightly poorer than the Clauss technique at low fibrinogen concentrations, equal to that at medium fibrinogen concentrations, and marginally better at high concentrations. Fibrinogen can therefore be measured reasonably accurately with the viscometric method, and can be recommended as an alternative for laboratories possessing a viscometer.

Adult↗
PubMed1991

Impaired blood rheology: a risk factor after stroke?

The hypothesis that blood rheology is of prognostic value in stroke patients was tested in a prospective study. A total of 523 patients in the rehabilitation phase of stroke (outside the acute phase reaction after stroke) were tested for blood, serum and plasma viscosity, haematocrit, fibrinogen, red cell aggregation and deformability, ESR, white cell count, cholesterol and triglycerides. Endpoints were defined as a second stroke (lethal or not) within 2 years after the initial examination. Patients suffering such endpoints exhibit elevated blood viscosity, red cell aggregation, plasma and serum viscosity, fibrinogen and cholesterol levels, compared to patients without endpoints. It is concluded that rheological factors are associated with the prognosis after a first stroke.

Aged↗
PubMed1991

Can rheologic variables be of prognostic relevance in arteriosclerotic diseases?

The hypothesis that blood rheology is of prognostic value in patients with arteriosclerotic diseases was tested in a prospective study of 843 patients at a rehabilitation clinic. They were tested for blood serum and plasma viscosity, hematocrit, fibrinogen, red cell aggregation and deformability, erythrocyte sedimentation rate, white cell count, cholesterol, and triglycerides. End points were defined as a second stroke or myocardial infarction or cardiovascular death within two years of the initial examination. Patients suffering such end points as compared with matched pairs (n = 74; matching criteria: identical manifestation of arteriosclerosis, identical sex and similar age and risk factors) had significantly higher native blood viscosity (p = 0.002), red cell aggregation (p = 0.01), serum viscosity (p = 0.01), fibrinogen (p = 0.02), and cholesterol (p = 0.01). It is concluded that rheologic factors are associated with the prognosis in patients with arteriosclerotic diseases.

Aged↗
PubMed1991

[Hemodilution in peripheral arterial occlusive disease. Placebo controlled randomized double-blind study with hydroxyethyl starch or dextran].

Hemodilution is often recommended for peripheral arterial occlusive disease, yet the ultimate proof of efficacy is lacking in two randomized, placebo-controlled, double-blind, crossover trials (one using Dextran 40 and the other 10% hydroxyethyl starch 200) it has been shown to clinically benefit claudicants. During the hemodilution phases of these trials, where a 500 ml volume was exchanged against 500 ml blood, there was a significant prolongation of the walking distances. With sham-hemodilution there were no beneficial effects. These studies suggest furthermore that responders and non-responders to hemodilution can be identified prior to therapy by angiogram. A theory is developed which implies that low shear forces in vivo are a precondition for the clinical effectiveness of hemodilution. The experimental evidence supporting this theory is reported. Dextran and hydroxyethyl starch do not seem to differ with respect to their clinical response. It is concluded that hemodilution is effective for peripheral arterial occlusive disease stage II and probably even more effective in more advanced stages.

Arterial Occlusive Diseases↗
PubMed1991

[Hemorheologic and clinical changes in ankylosing spondylitis during hyperthermia].

In this controlled study the short- and longterm effects of whole body hyperthermia in ankylosing spondylitis were investigated. Longitudinal and cross-sectional analyses show positive effects: reduction in blood and plasma viscosity, normalization of red cell deformability, reduction of analgetics' use, increase in motility and subjective improvement of well-being. Clinical and rheological changes correlate which might imply (but does not prove) a causal relationship between the two.

Adult↗
PubMed1991

[Hyperviscosity. An independent risk factor after a survived stroke].

Several lines of evidence indicate that pathologic blood flow properties lead to a deterioration in the prognosis of patients with arteriosclerotic diseases, especially after a stroke. We tested this hypothesis in a prospective study including 625 patients with a first stroke that dated back less than five years (7.4 +/- 11.3 months, mean +/- sd). Investigated parameters were native and hematocrit standardized blood viscosity (at shear rates 0.7 s-1, 2.4 s-1 and 95.5 s-1) and its most important determinants (i.e. hematocrit, plasma viscosity, fibrinogen), erythrocyte sedimentation rate, leukocytes, cholesterol, triglycerides, blood pressure and BMI. For smoking patients were scored into four groups. Two years after these investigations a follow up was performed (response rate 96.3%). 71 patients with study endpoint (second stroke, heart attack or death due to the underlying cardiovascular disease) were identified. In 65 cases matching of a patient with and a patient without endpoint was possible. Criteria for matching were: cholesterol, triglycerides, diabetes, BMI, gender, age blood pressure, smoking, time interval between first stroke and rheologic measurements and concomitant diseases. Native blood viscosity was significantly higher in patients with endpoint (p less than 0.01) as compared to patients without (37.4 +/- 12.5 mPas vs 32.1 +/- 8.9 mPas at a shear rate of 0.7 s-1). All other variables did not differ significantly between both groups. It is concluded that in patients, who have survived a first stroke, high blood viscosity is a risk factor, independent from the accepted ones.

Blood Flow Velocity↗
PubMed1990

A double-blind trial of Dextran-haemodilution vs. placebo in claudicants.

Haemodilution is often recommended for peripheral arterial disease, yet little data is available to support its clinical efficacy. This study was designed to prove or disprove the effectiveness of Dextran-haemodilution in intermittent claudication. Twenty claudicants with long, well-collateralized arterial occlusions were randomized into groups 1 and 2. Group 1 received isovolemic haemodilution with Dextran 40 (500 ml per session) during 3 weeks, which was followed by a wash-out period, followed by placebo treatments for 3 weeks. In group 2 this sequence was reversed. Pain-free and maximal walking distances were measured by standardized treadmill tests along with plethysmographic blood flow, Doppler pressures, haematocrit, blood and plasma viscosity as well as fibrinogen. Walking distances increased significantly by about 50% during haemodilution in both groups. This was paralleled by a fall in haematocrit and blood viscosity. All other variables remained constant. During placebo treatments there were no significant changes of any variable. The treatment was tolerated without complications. Thus Dextran-haemodilution seems safe and effective in selected peripheral occlusive arterial disease (POAD) patients. Potential responders might be identifiable before the start of therapy by angiographic investigations. The clinical effectiveness of Dextran 40 is comparable to that of hydroxyethyl starch 200 as reported in the literature.

Adult↗
PubMed1989

Hemorheological effects of oral contraceptives.

To determine the hemorheological effects of oral contraceptives, 50 healthy young women took no medication for 3 cycles. Subsequently they were randomized into group A and B. Group A took Diane-35, B took Microgynon each for 6 cycles. Finally 3 cycles without medication followed. Blood viscosity was quantified by ex vivo measurements of hematocrit, blood and plasma viscosity, red cell filterability, fibrinogen and colloid oncotic pressure. In group A fibrinogen rose at the end of the medication phase. In group B fibrinogen, blood and plasma viscosity increased on medication. The former 2 variables remained elevated even after discontinuation of the oral contraceptive. The data combined with those from the literature suggest that low-dose oral contraceptives lead to no biologically meaningful changes in blood rheology while higher doses induce limitations of blood fluidity which could be involved in the increment of cardiovascular risk by these medications.

Adult↗
PubMed1989

Leucocyte aggregation in burned patients.

Leucocyte aggregation describes one type of biophysical behaviour of white cells. To test whether this parameter is changed in burned patients, 15 burn victims were investigated immediately after admission into hospital. Cell counts and aggregation were measured and related to the prognosis of the injury. Compared with normal controls, burning injury is associated with higher white cell counts and enhanced leucocyte aggregation. Fatal injuries showed a (non-significant) tendency for higher aggregation values than survivors. There are significant positive correlations between white cell counts, maximal aggregation values and the burned body surface area. The results suggest that leucocyte aggregation is pathologically enhanced in response to burns. Possibly this alteration is of prognostic importance.

Adult↗
PubMed1989

Is increased plasma viscosity a risk factor for high blood pressure?

Data from several epidemiologic studies have suggested that, among other variables, hematocrit and fibrinogen may constitute risk factors for high blood pressure. As part of a population survey for cardiovascular risk factors, plasma viscosity and hemoglobin were measured. Blood pressure was determined under standardized conditions according to the recommendations of the AHA. A two-stage age-sex-stratified cluster sample of 5,312 persons, aged twenty-five to sixty-four years, was selected from a mixed urban/rural target population of 282,279 (total population approximately 533,000). A net response of 79.3% was achieved. Multiple logistic regression analyses including plasma viscosity, hemoglobin, body mass index, alcohol consumption, smoking behavior, and total serum cholesterol as independent variables were run controlling for both age and sex. Plasma viscosity appeared as a significant main effect in all analyses and demonstrated the strongest association with high blood pressure next to body mass index. Whether this association implies a causal relationship cannot be answered from cross-sectional data. However, even if plasma hyperviscosity represents a secondary phenomenon in hypertension, it might be of prognostic relevance. There is evidence that increased plasma viscosity may contribute to myocardial hypertrophy. Therefore hypertensives with impaired blood fluidity might constitute a subgroup at particular risk for cardiovascular complications. When antihypertensive drugs are selected, their influence on blood viscosity should be taken into account.

Adult↗
PubMed1989

Placebo-controlled, double-blind trial of hemodilution in peripheral occlusive arterial disease.

A number of uncontrolled trials has suggested that hemodilution is effective in peripheral occlusive arterial disease. This study was aimed at proving or disproving the efficacy of hemodilution by using a randomized, placebo-controlled, double-blind crossover design. Twenty-four stable claudicants with long, collateralized femoropopliteal obstructions were treated with isovolemic hemodilution with 500 mL of 10% hydroxyethyl starch 200 and sham dilutions. Three weeks of hemodilution lowered blood and plasma viscosity, as well as hematocrit, and increased resting blood flow and pain-free walking distance. Placebo treatments produced no such favorable changes. It is concluded that hemodilution therapy can be clinically effective in patients with arterial obstructions in the lower extremities. Hemodilution seems particularly promising under hemodynamic condition of low shear stresses in vivo.

Blood Viscosity↗
PubMed1989

Changes in blood rheology of grossly obese individuals during a very low calorie diet.

A group of grossly obese individuals were put on a 300 kcal diet for 15 days. Blood rheology was quantified by measuring blood and plasma viscosity, haematocrit, red cell aggregation and deformability, fibrinogen and ESR. After 15 days blood viscosity had decreased and red cell deformability increased. The results suggest that the rheological deficit in obesity can be partly normalized by low calorie diets.

Blood Viscosity↗
PubMed1988

Blood rheology in patients with transient ischemic attacks.

A complete ischemic stroke is associated with a significant hemorheologic disturbance leading to a rise of the viscous component of the peripheral resistance. This abnormality represents a consequence of the acute event. Nonetheless, it could be causally related to ischemia. In an attempt to clarify this question, 26 patients suffering from transient ischemic attacks were compared with controls in terms of blood and plasma viscosity, hematocrit, blood cell filterability, and erythrocyte aggregation. In patients there was a significant impairment of blood fluidity comprising plasma viscosity, blood cell filterability, and erythrocyte aggregation, suggesting that the flow properties of blood are jeopardized even before an acute stroke. Most likely this is due to the underlying arteriosclerotic process. Our results open the way to speculating that hemorheologic mechanisms might predispose to the development of a stroke by decreasing cerebral blood flow. If this hypothesis were true, it would have important therapeutic implications.

Adult↗
PubMed1988

Blood rheology associated with cardiovascular risk factors and chronic cardiovascular diseases: results of an epidemiologic cross-sectional study.

As part of an epidemiologic cross-sectional study to determine cardiovascular (CV) risk factors in the population (total serum cholesterol, smoking, blood pressure, and body weight) hemoglobin (Hb) and plasma viscosity (PV) were measured. A two-stage cluster sample of 5,312 persons, aged twenty-five to sixty-four (available 5,069) was selected from a mixed urban-rural target population of 282,279 inhabitants, from which 4,022 (79.3%) participated in the study. Patients with chronic myocardial infarction (MI), cerebral infarction (CI), angina pectoris (AP), and peripheral arterial disease (PAD) were identified by questionnaire. The results show that there is no age or sex dependency of PV in healthy participants, while hemoglobin shows the well-known sex difference. In contrast, PV increases continuously with age in the total population. In men, increased PV is found in untreated hypertension, in hypercholesterolemia, and in smokers. In women, it is raised in hypercholesterolemia and in gross obesity. Male MI patients and patients of both sexes after CI in particular show statistically significantly elevated PV. Finally, in male patients with chronic AP or patients of both sexes with PAD, PV is elevated and a tendency to higher Hb values is seen. These results confirm smaller clinical trials suggesting that blood fluidity is pathologically altered in patients with CV risk factors or diseases. Since impaired blood fluidity may worsen the hemodynamic situation, in particular in patients with limited vasomotor reserve, hemorheologic parameters may be of prognostic relevance. Therapeutic implications of these findings should be considered.

Adult↗